\begin{tikzpicture}[>=Stealth, scale=0.5,
    every label/.style={fill=white, inner sep=1pt},
]
    \draw [->] (-6, 0) -- (5, 0) node[below=0.2em] {$x$};
    \draw [->] (0, -2) -- (0, 5.5) node[left=0.2em] {$y$};
    \draw (0, 0) node [below left] {\small $O$};
    \foreach \x in {-4,...,3} {
        \draw (\x, 0) -- (\x, 0.2);
    }
    \foreach \y in {1,...,3} {
        \draw (-0.2, \y) -- (0, \y);
    }

    \coordinate [label=left:\small $A$] (A) at (-1, 3);
    \coordinate [label=left:\small $B$] (B) at (3, 0);
    \coordinate [label=left:\small $C$] (C) at (-4, 0);
    \pgfmathsetmacro{\r}{0.7}
    \pgfmathsetmacro{\R}{1.2}

    \filldraw [fill=black] (A) circle (0.05);
    \filldraw [fill=black] (B) circle (0.05);
    \filldraw [fill=black] (C) circle (0.05);

    \draw [thick] (A) circle (\r);
    \draw [thick] (B) circle (\r);
    \draw [thick] (C) circle (\r);

    \path (A) +(30:\R)  coordinate(pa);
    \path (C) +(150:\R) coordinate(pc);
    \path (B) +(270:\R) coordinate(pb);

    \draw [rounded corners] (pa)
        arc [radius=\R, start angle=30,  end angle=150]
        -- (pc)
        arc [radius=\R, start angle=150, end angle=270]
        -- (pb)
        arc [radius=\R, start angle=270, end angle=390]
        -- (pa);
\end{tikzpicture}

